1. Field of the Invention
The present invention relates to a touch display technology, and more particular to a self-capacitive touch panel structure, an in-cell touch panel, and a liquid crystal display.
2. Description of Related Art
A touch panel as an input medium is the most simple and convenient human-computer interaction method. Therefore, the touch panel is more widely applied to a variety of electronic products. Based on different operation principles and interfaces for transmitting information, touch panel products can divide into four types: an infrared touch panel, a capacitive touch panel, a resistive touch panel and a surface acoustic wave touch panel. Wherein, the capacitive touch panel becomes the mainstream of touch panel technology because a long life, high transmittance, capable of supporting multiple touches, etc. The capacitive touch panel includes a surface capacitive type and a projected capacitive type. The projected capacitive type can be divided into a self-capacitive type and a mutual capacitive type. The self-capacitive touch panel structure, due to higher touch sensing accuracy and signal to noise ratio are favored by major panel manufacturers.
Currently, the self-capacitive touch panel structure utilizes a self-capacitance principle to detect a touch location of a finger. Specifically, multiple self-capacitance electrodes which are disposed at a same layer and isolated with each other are disposed in the touch panel structure. When a human body does not contact with the touch panel, a capacitance applied on each self-capacitance electrode is a fixed value. When a human body contact with the touch panel, a capacitance applied on a self-capacitance electrode which is corresponding to a touch location is the fixed value adding a human capacitance. A touch detection chip can determine the touch location in a touch time interval through detecting a capacitance change of each self-capacitance electrode.
FIG. 1 is a schematic diagram of a self-capacitive touch panel structure according to the conventional art. As shown in FIG. 1, the self-capacitive touch panel includes M rows and columns self-capacitance electrodes Rxy (R11˜RM1˜R1N˜RMN), and a touch detection chip 1. Each self-capacitance electrode Rxy utilizes a single connection line Lyx to connect with the touch detection chip 1. Specifically, the self capacitance electrodes Rxy and the connection lines Lyx are disposed at different layers, and each self-capacitance electrode Rxy utilizes a via hole 2 to electrically connect with a corresponding connection line Lyx. That is, each column of the self capacitance electrodes R1y˜RMy is sequentially connected with a group of the connection lines Ly1˜LyM in order.
As sown in FIG. 1, from a bottom side to a top side, the first column of the self capacitance electrodes R11˜RM1 are respectively corresponded to a group of the connection lines L11˜L1M which are from a left side to a right side. Each connection line L1x is connected with a corresponding self-capacitance electrode Rx1, and each connection line L1x is disconnected with other self-capacitance electrodes in order to realize an independent control of each self-capacitance electrode Rx1. That is, each self-capacitance electrode Rx1 connected with the connection line L1x is not connected with previous self-capacitance electrodes R11˜R(x−1)1. After the connection line L1x is connected with the corresponding self-capacitance Rx1, the connection line L1x does not connect with following self-capacitance electrodes R(x+1)1˜RM1.
Specifically, the first self-capacitance electrode R11 of the self-capacitance electrodes R11˜RM1 is connected with the touch detection chip 1 through the first connection line L11 of the group of the connection lines L11˜L1M, the second self-capacitance electrode R21 of the self-capacitance electrodes R11˜RM1 is connected with the touch detection chip 1 through the second connection line L12 of the group of the connection lines L11˜L1M, and so on, the Mth self-capacitance electrode RM1 is connected with the touch detection chip 1 through the Mth connection line L1M. Wherein, in the above symbols, x=1, 2, 3 . . . , M; y=1, 2, 3 . . . , N.
In the structure of the self-capacitive touch panel described above, because each column of the self-capacitance electrodes R1y˜RMy is sequentially connected with a group of the connection lines Ly1˜LyM in order. For the same column of the self-capacitance electrodes R1y˜RMy, lengths of the group of the connection lines Ly1˜LyM corresponding to the column are increased gradually. The self-capacitance electrode RMy farther away from the touch detection chip 1, the corresponding resistance value is larger. Finally, for the display situation of entire structure of the touch panel, resistance values of the connection lines Lyx at different areas are unbalance so as to affect the sensitivity of the touch panel and the display effect of the product.